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* [Intel-gfx] [PATCH] drm/i915/gt: Mark up the racy read of execlists->context_tag
@ 2020-05-09  9:42 Chris Wilson
  2020-05-09 10:13 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
  2020-05-09 13:49 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
  0 siblings, 2 replies; 3+ messages in thread
From: Chris Wilson @ 2020-05-09  9:42 UTC (permalink / raw)
  To: intel-gfx; +Cc: Chris Wilson

Since we are using bitops on context_tag to allow us to reserve and
release inflight tags concurrently, the scan for the next bit is
intentionally racy.

[  516.446854] BUG: KCSAN: data-race in execlists_schedule_in.isra.0 [i915] / execlists_schedule_out [i915]
[  516.446874]
[  516.446886] write (marked) to 0xffff8881f7644048 of 8 bytes by interrupt on cpu 2:
[  516.447076]  execlists_schedule_out+0x538/0x6a0 [i915]
[  516.447263]  process_csb+0x10b/0x3d0 [i915]
[  516.447449]  execlists_submission_tasklet+0x30/0x170 [i915]
[  516.447468]  tasklet_action_common.isra.0+0x42/0x90
[  516.447484]  __do_softirq+0xc8/0x206
[  516.447498]  irq_exit+0xcd/0xe0
[  516.447516]  do_IRQ+0x44/0xc0
[  516.447535]  ret_from_intr+0x0/0x1c
[  516.447550]  cpuidle_enter_state+0x199/0x400
[  516.447572]  cpuidle_enter+0x50/0x90
[  516.447587]  do_idle+0x197/0x1e0
[  516.447600]  cpu_startup_entry+0x14/0x20
[  516.447619]  start_secondary+0xf9/0x130
[  516.447643]  secondary_startup_64+0xa4/0xb0
[  516.447655]
[  516.447671] read to 0xffff8881f7644048 of 8 bytes by task 460 on cpu 1:
[  516.447863]  execlists_schedule_in.isra.0+0x3cf/0x5a0 [i915]
[  516.448064]  execlists_dequeue+0xf8f/0x1690 [i915]
[  516.448252]  __execlists_submission_tasklet+0x48/0x60 [i915]
[  516.448440]  execlists_submit_request+0x2e2/0x310 [i915]
[  516.448634]  submit_notify+0x8f/0xc8 [i915]
[  516.448820]  __i915_sw_fence_complete+0x61/0x420 [i915]
[  516.449005]  i915_sw_fence_complete+0x58/0x80 [i915]
[  516.449208]  i915_sw_fence_commit+0x16/0x20 [i915]
[  516.449399]  __i915_request_queue+0x60/0x70 [i915]
[  516.449590]  i915_gem_do_execbuffer+0x33f1/0x4a00 [i915]
[  516.449782]  i915_gem_execbuffer2_ioctl+0x2a2/0x550 [i915]
[  516.449800]  drm_ioctl_kernel+0xe9/0x130
[  516.449814]  drm_ioctl+0x27d/0x45e
[  516.449827]  ksys_ioctl+0x89/0xb0
[  516.449842]  __x64_sys_ioctl+0x42/0x60
[  516.449864]  do_syscall_64+0x6e/0x2c0
[  516.449878]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 28b477f531a5..e78d7429defa 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1367,7 +1367,7 @@ __execlists_schedule_in(struct i915_request *rq)
 		ce->lrc.ccid = ce->tag;
 	} else {
 		/* We don't need a strict matching tag, just different values */
-		unsigned int tag = ffs(engine->context_tag);
+		unsigned int tag = ffs(READ_ONCE(engine->context_tag));
 
 		GEM_BUG_ON(tag == 0 || tag >= BITS_PER_LONG);
 		clear_bit(tag - 1, &engine->context_tag);
-- 
2.20.1

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

^ permalink raw reply related	[flat|nested] 3+ messages in thread
* [Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915/gt: Mark up the racy read of execlists->context_tag
  2020-05-09  9:42 [Intel-gfx] [PATCH] drm/i915/gt: Mark up the racy read of execlists->context_tag Chris Wilson
@ 2020-05-09 10:13 ` Patchwork
  2020-05-09 13:49 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
  1 sibling, 0 replies; 3+ messages in thread
From: Patchwork @ 2020-05-09 10:13 UTC (permalink / raw)
  To: Chris Wilson; +Cc: intel-gfx

== Series Details ==

Series: drm/i915/gt: Mark up the racy read of execlists->context_tag
URL   : https://patchwork.freedesktop.org/series/77099/
State : success

== Summary ==

CI Bug Log - changes from CI_DRM_8456 -> Patchwork_17614
====================================================

Summary
-------

  **SUCCESS**

  No regressions found.

  External URL: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/index.html

Known issues
------------

  Here are the changes found in Patchwork_17614 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@i915_selftest@live@sanitycheck:
    - fi-bwr-2160:        [PASS][1] -> [INCOMPLETE][2] ([i915#489])
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/fi-bwr-2160/igt@i915_selftest@live@sanitycheck.html
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/fi-bwr-2160/igt@i915_selftest@live@sanitycheck.html

  
  [i915#489]: https://gitlab.freedesktop.org/drm/intel/issues/489


Participating hosts (48 -> 42)
------------------------------

  Missing    (6): fi-ilk-m540 fi-hsw-4200u fi-byt-squawks fi-bsw-cyan fi-byt-clapper fi-bdw-samus 


Build changes
-------------

  * CI: CI-20190529 -> None
  * Linux: CI_DRM_8456 -> Patchwork_17614

  CI-20190529: 20190529
  CI_DRM_8456: 4027cd5e6a38cb88b4ae0296d2f06daf8944f26b @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_5643: 9d0576c821f886fd053effd96cd3c441fee2ce53 @ git://anongit.freedesktop.org/xorg/app/intel-gpu-tools
  Patchwork_17614: 667a54b0c4c137832da216fc858a12f828d9adbf @ git://anongit.freedesktop.org/gfx-ci/linux


== Linux commits ==

667a54b0c4c1 drm/i915/gt: Mark up the racy read of execlists->context_tag

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/index.html
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

^ permalink raw reply	[flat|nested] 3+ messages in thread
* [Intel-gfx] ✓ Fi.CI.IGT: success for drm/i915/gt: Mark up the racy read of execlists->context_tag
  2020-05-09  9:42 [Intel-gfx] [PATCH] drm/i915/gt: Mark up the racy read of execlists->context_tag Chris Wilson
  2020-05-09 10:13 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
@ 2020-05-09 13:49 ` Patchwork
  1 sibling, 0 replies; 3+ messages in thread
From: Patchwork @ 2020-05-09 13:49 UTC (permalink / raw)
  To: Chris Wilson; +Cc: intel-gfx

== Series Details ==

Series: drm/i915/gt: Mark up the racy read of execlists->context_tag
URL   : https://patchwork.freedesktop.org/series/77099/
State : success

== Summary ==

CI Bug Log - changes from CI_DRM_8456_full -> Patchwork_17614_full
====================================================

Summary
-------

  **SUCCESS**

  No regressions found.

  

Known issues
------------

  Here are the changes found in Patchwork_17614_full that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@i915_suspend@debugfs-reader:
    - shard-skl:          [PASS][1] -> [INCOMPLETE][2] ([i915#69])
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-skl8/igt@i915_suspend@debugfs-reader.html
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-skl7/igt@i915_suspend@debugfs-reader.html

  * igt@kms_color@pipe-b-legacy-gamma:
    - shard-snb:          [PASS][3] -> [SKIP][4] ([fdo#109271]) +6 similar issues
   [3]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-snb2/igt@kms_color@pipe-b-legacy-gamma.html
   [4]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-snb1/igt@kms_color@pipe-b-legacy-gamma.html

  * igt@kms_cursor_legacy@2x-long-flip-vs-cursor-atomic:
    - shard-glk:          [PASS][5] -> [FAIL][6] ([i915#72])
   [5]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-glk8/igt@kms_cursor_legacy@2x-long-flip-vs-cursor-atomic.html
   [6]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-glk1/igt@kms_cursor_legacy@2x-long-flip-vs-cursor-atomic.html

  * igt@kms_hdr@bpc-switch:
    - shard-skl:          [PASS][7] -> [FAIL][8] ([i915#1188])
   [7]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-skl9/igt@kms_hdr@bpc-switch.html
   [8]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-skl5/igt@kms_hdr@bpc-switch.html

  * igt@kms_psr@psr2_cursor_mmap_cpu:
    - shard-iclb:         [PASS][9] -> [SKIP][10] ([fdo#109441]) +4 similar issues
   [9]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-iclb2/igt@kms_psr@psr2_cursor_mmap_cpu.html
   [10]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-iclb4/igt@kms_psr@psr2_cursor_mmap_cpu.html

  * igt@kms_setmode@basic:
    - shard-kbl:          [PASS][11] -> [FAIL][12] ([i915#31])
   [11]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-kbl6/igt@kms_setmode@basic.html
   [12]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-kbl6/igt@kms_setmode@basic.html

  
#### Possible fixes ####

  * igt@kms_cursor_legacy@all-pipes-torture-move:
    - shard-tglb:         [DMESG-WARN][13] ([i915#128]) -> [PASS][14]
   [13]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-tglb2/igt@kms_cursor_legacy@all-pipes-torture-move.html
   [14]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-tglb2/igt@kms_cursor_legacy@all-pipes-torture-move.html

  * {igt@kms_flip@flip-vs-suspend-interruptible@a-dp1}:
    - shard-apl:          [DMESG-WARN][15] ([i915#180]) -> [PASS][16] +1 similar issue
   [15]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-apl1/igt@kms_flip@flip-vs-suspend-interruptible@a-dp1.html
   [16]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-apl6/igt@kms_flip@flip-vs-suspend-interruptible@a-dp1.html

  * {igt@kms_flip@flip-vs-suspend@a-edp1}:
    - shard-skl:          [INCOMPLETE][17] ([i915#198]) -> [PASS][18]
   [17]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-skl2/igt@kms_flip@flip-vs-suspend@a-edp1.html
   [18]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-skl4/igt@kms_flip@flip-vs-suspend@a-edp1.html

  * igt@kms_flip_tiling@flip-x-tiled:
    - shard-skl:          [FAIL][19] ([fdo#108145] / [i915#699]) -> [PASS][20]
   [19]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-skl9/igt@kms_flip_tiling@flip-x-tiled.html
   [20]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-skl5/igt@kms_flip_tiling@flip-x-tiled.html

  * igt@kms_frontbuffer_tracking@psr-1p-primscrn-pri-indfb-draw-mmap-wc:
    - shard-skl:          [FAIL][21] ([i915#49]) -> [PASS][22]
   [21]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-skl7/igt@kms_frontbuffer_tracking@psr-1p-primscrn-pri-indfb-draw-mmap-wc.html
   [22]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-skl3/igt@kms_frontbuffer_tracking@psr-1p-primscrn-pri-indfb-draw-mmap-wc.html

  * igt@kms_plane_lowres@pipe-a-tiling-x:
    - shard-glk:          [FAIL][23] ([i915#899]) -> [PASS][24]
   [23]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-glk4/igt@kms_plane_lowres@pipe-a-tiling-x.html
   [24]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-glk2/igt@kms_plane_lowres@pipe-a-tiling-x.html

  * igt@kms_psr@psr2_primary_mmap_cpu:
    - shard-iclb:         [SKIP][25] ([fdo#109441]) -> [PASS][26] +2 similar issues
   [25]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-iclb5/igt@kms_psr@psr2_primary_mmap_cpu.html
   [26]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-iclb2/igt@kms_psr@psr2_primary_mmap_cpu.html

  
#### Warnings ####

  * igt@kms_content_protection@atomic-dpms:
    - shard-apl:          [TIMEOUT][27] ([i915#1319]) -> [FAIL][28] ([fdo#110321] / [fdo#110336])
   [27]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-apl3/igt@kms_content_protection@atomic-dpms.html
   [28]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-apl8/igt@kms_content_protection@atomic-dpms.html

  * igt@kms_content_protection@legacy:
    - shard-apl:          [FAIL][29] ([fdo#110321] / [fdo#110336]) -> [TIMEOUT][30] ([i915#1319])
   [29]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-apl1/igt@kms_content_protection@legacy.html
   [30]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-apl3/igt@kms_content_protection@legacy.html

  * igt@kms_frontbuffer_tracking@fbc-1p-primscrn-cur-indfb-draw-mmap-wc:
    - shard-apl:          [FAIL][31] ([i915#49] / [i915#95]) -> [FAIL][32] ([i915#49])
   [31]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8456/shard-apl8/igt@kms_frontbuffer_tracking@fbc-1p-primscrn-cur-indfb-draw-mmap-wc.html
   [32]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/shard-apl6/igt@kms_frontbuffer_tracking@fbc-1p-primscrn-cur-indfb-draw-mmap-wc.html

  
  {name}: This element is suppressed. This means it is ignored when computing
          the status of the difference (SUCCESS, WARNING, or FAILURE).

  [fdo#108145]: https://bugs.freedesktop.org/show_bug.cgi?id=108145
  [fdo#109271]: https://bugs.freedesktop.org/show_bug.cgi?id=109271
  [fdo#109441]: https://bugs.freedesktop.org/show_bug.cgi?id=109441
  [fdo#110321]: https://bugs.freedesktop.org/show_bug.cgi?id=110321
  [fdo#110336]: https://bugs.freedesktop.org/show_bug.cgi?id=110336
  [i915#1188]: https://gitlab.freedesktop.org/drm/intel/issues/1188
  [i915#128]: https://gitlab.freedesktop.org/drm/intel/issues/128
  [i915#1319]: https://gitlab.freedesktop.org/drm/intel/issues/1319
  [i915#180]: https://gitlab.freedesktop.org/drm/intel/issues/180
  [i915#198]: https://gitlab.freedesktop.org/drm/intel/issues/198
  [i915#31]: https://gitlab.freedesktop.org/drm/intel/issues/31
  [i915#49]: https://gitlab.freedesktop.org/drm/intel/issues/49
  [i915#69]: https://gitlab.freedesktop.org/drm/intel/issues/69
  [i915#699]: https://gitlab.freedesktop.org/drm/intel/issues/699
  [i915#72]: https://gitlab.freedesktop.org/drm/intel/issues/72
  [i915#899]: https://gitlab.freedesktop.org/drm/intel/issues/899
  [i915#95]: https://gitlab.freedesktop.org/drm/intel/issues/95


Participating hosts (11 -> 11)
------------------------------

  No changes in participating hosts


Build changes
-------------

  * CI: CI-20190529 -> None
  * Linux: CI_DRM_8456 -> Patchwork_17614

  CI-20190529: 20190529
  CI_DRM_8456: 4027cd5e6a38cb88b4ae0296d2f06daf8944f26b @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_5643: 9d0576c821f886fd053effd96cd3c441fee2ce53 @ git://anongit.freedesktop.org/xorg/app/intel-gpu-tools
  Patchwork_17614: 667a54b0c4c137832da216fc858a12f828d9adbf @ git://anongit.freedesktop.org/gfx-ci/linux
  piglit_4509: fdc5a4ca11124ab8413c7988896eec4c97336694 @ git://anongit.freedesktop.org/piglit

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17614/index.html
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-05-09 13:49 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-09  9:42 [Intel-gfx] [PATCH] drm/i915/gt: Mark up the racy read of execlists->context_tag Chris Wilson
2020-05-09 10:13 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2020-05-09 13:49 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork

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